This research program involves studies of the application of mass spectrometry to molecular structure determination and analysis applicable to biomedical research. Chemical ionization is a new tool for stereochemical differentiation of substituted cyclic molecules. A Self-Training Interpretive and Retrieval System can now find the structural features of closest mass spectral behavior by a search through a file of 24,000 reference mass spectra in 80 seconds, and give quantitative confidence levels for the identification of particular functionalities. High speed liquid chromatography can be monitored by direct introduction of solutions into a chemical ionization mass spectrometer. Collisional activation analysis has made possible the characterization of the structures of a substantial number and variety of ions.